Others have said the same thing, but: Anonymous in general has terrible politics, although the dynamism to its subculture occasionally gives rise to politically important factions. Elements of Anonymous completely fell for a CIA-designed color revolution attempt in Iran in 2009 (designed to impose an extreme neoliberal regime in Iran under Mousavi; the economic class elements of Ahmadinejad’s and Mousavi’s respective bases of support should also be noted) and at its worst at times “Anonymous” is purely a front for overt US government activity.
Noting the imperialist maneuvers around the Korean peninsula, this sort of hacking in context would be as if “Anonymous” attacked servers of Saddam Hussein’s government in the immediate period before Bush’s invasion clearly loomed. It’s like, basically declaring yourself as a co-belligerent of genocidal imperialists. US has always refused to sign a peace treaty with the DPRK despite extended pleas — who is the real “threat to peace”? Why does the US insist on maintaining a state of war? How can we judge the DPRK for maintaining a militarized economy in the face of the diplomatic reality of an imposed state of perpetual war?
US imperialism regularly organizes “regime change” attempts against targeted nations through internet subcultural means; all imposed “color revolutions” by the US State Department and George Soros have been more authoritarian and less economically progressive than the regimes they replaced regardless of initial “free speech” rhetoric often accompanying their ascent (which nevertheless is usually openly neoliberal and pro-western imperialist in orientation).
Hackers linked to Anonymous are only arrested when they target the US government itself or its close corporate or nation-state allies (particularly Israel or firms linked to Israeli intelligence such as Stratfor). What that says should be obvious. The US government has its own “gangs” within Anonymous that it protects (charting the entire terrain would take time).